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Lubrication of windmilling journal bearings

Active Publication Date: 2008-04-24
RAYTHEON TECH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009]During windmilling fan operation, the planet gears continue to rotate in the same rotational direction at a slower rotational speed. Because of the slower speed, less oil is required to lubricate the journal bearings

Problems solved by technology

When the engine in not operating, wind passing through the fan can cause the fan to rotate, or windmill, even though the fan is not being driven by the fan drive gear system.

Method used

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  • Lubrication of windmilling journal bearings
  • Lubrication of windmilling journal bearings
  • Lubrication of windmilling journal bearings

Examples

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Embodiment Construction

[0018]FIG. 1 is a schematic view of a portion of a turbine engine 10. The turbine engine 10 includes a fixed housing 12 that is constructed from numerous pieces secured to one another. A compressor section 14 has compressor hubs 16 with blades. A turbine shaft 25 drives the hubs 16 about an axis A. A fan 18 is supported on a fan shaft 20 that is driven by a turbine flexible coupling 30 through a gear set 28.

[0019]FIG. 2 schematically illustrates a fan drive system 26 for the fan 18. The gear set 28 is preferably an epicyclic gear set including the turbine flexible coupling 30, which drives the fan 18. An oil supply system 32 supplies oil to the epicyclic gear set 28. The oil supply system 32 includes a primary oil pump 34 which provides oil from an oil supply 36 during driven operation of the fan 18. A secondary oil pump 38 provides oil from an internal sump 35 during windmilling operation of the fan 18.

[0020]Referring to FIG. 3, an example epicyclic gear set 28 is illustrated. A su...

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Abstract

A support shaft provides lubrication to a journal bearing during windmilling operation of a gear set. A primary oil pump provides oil from an oil supply during driven operation of the fan, and a secondary oil pump provides oil from an internal sump during windmilling operation of the fan. During driven operation of the fan, oil is pumped with the primary oil pump through a primary oil flow path to an outer surface of the support shaft. During windmilling fan operation, oil is pumped from an internal sump with a secondary oil pump through the secondary oil flow path. The secondary oil flow path has a smaller flow capacity, and the secondary oil pump is a smaller capacity pump.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates to an arrangement for supplying oil to journal bearings for use in fan drive systems for turbofan engines.[0002]Turbine engines use epicyclic gear systems to drive fans or propellers during engine operation. Journal bearings are utilized in the gear systems to transfer torque between planet gears and corresponding support shafts. Oil is supplied from an oil system to lubricate each of the journal bearings. An oil pump maintains pressure within the oil system to ensure each of the journal bearings receives an adequate supply of oil.[0003]During operation, the gas turbine can be shut down for various reasons. When the gas turbine is not operating, the oil pump may also shut down. However, due to the force of the wind, the fan will continue to rotate, or windmill, even while the engine is not driving the fan. Without some oil supply, the journal bearings may seize and stop engine rotation.[0004]The required oil supply for a windmi...

Claims

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Application Information

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IPC IPC(8): F16H57/04
CPCF01D25/20F16C33/66F16H57/04F05D2270/09F16H57/0479F05D2260/40311F16H57/0434F16C2360/23F16C17/02F16C33/1055F16C2361/61
Inventor MCCUNE, MICHAEL E.
Owner RAYTHEON TECH CORP
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